13.4 MRI Weightings

This section deals with T1 and T2 weightings.

13.4.1 T1 Weighting

T~1~ Weighting

Figure 13.15: T1 Weighting

In a T1 weighting, all curves in the above figure come together at long TRs. A long TR will minimize the effect of a T1 contrast.

A short TR of about 500 milliseconds to about 1500 milliseconds will give a good T1 contrast between all three tissue types.

13.4.2 T2 Weighting

T~2~ Image Weightings

Figure 13.16: T2 Image Weightings

T~2~ Images with Varying Contrasts

Figure 13.17: T2 Images with Varying Contrasts

A short TE (i.e., about 20 milliseconds) leads to a short T2 contrast, while a longer TE (i.e., about 50 milliseconds) has a good separation between each tissue type.

13.4.3 Differences in T1 and T2 Weightings

Differences Between T~1~ and T~2~ Weighted Images

Figure 13.18: Differences Between T1 and T2 Weighted Images

Both of the above images can be used to diagnose any abnormalities that may be in the patient.

13.4.4 Proton Density (i.e., PD) Weightings

Proton Density Weighting

Figure 13.19: Proton Density Weighting

In this kind of weighting, tissues that have the most protons have the highest signals and are hence the brightest in the image.